Have you tried clearing the Avada Cache files? Did you by any chance already try downloading a fresh copy of Avada and then completely replace the Avada template directory with a fresh copy?
I have had minor issues after upgrades in the past and one or both of these options has helped. I haven’t had an issue with the Avada template since I switch hosting companies though. To many hosts still use older versions of PHP because of the mass amounts of different websites they host on one server.